Orthogonal test design for optimization of the extraction of flavonid from the Fructus Gardeniae.

Objective: It is imperative to provide some consistent experimental results for the extraction of flavonid from Fructus Gardeniae.

Methods: The key extraction parameters that influenced the yield of flavonid from Fructus Gardeniae were optimized by employing an orthogonal experiment [L(9)(3)(4)], including the ratio of buffer solution (Na(2)B(4)O(7)·10H(2)O) to raw material, concentration of Fructus Gardeniae in extracting solution, extraction time and pH of buffer solution. An UV/Vis detector was used to perform the qualitative and quantitative analyses of the extracted flavonid with the using of the standard sample.

Results: The maximum extraction yield of the crude extract was 5.0533 (mg/g) after 20 min when the mass ratio of Na(2)B(4)O(7)·10H(2)O to raw material was 0.4%, the concentration of Fructus Gardeniae in the extraction solution was 1/12 (g/mL), and pH of buffer solution was 4.5. The positive reactions to the Molish and HCl-Mg tests suggested that the extracted compound was flavonoid, and FTIR measurements also identified the presence of flavonoid in the extracts.

Conclusion: This work is expected to provide a basis for further research, development, and utilization of Fructus gardenia in flavonid extraction.